The EA Forums have a confirmation of widespread suspicions that Battlefield 3 will not be sold through Valve's Steam platform (thanks Planet Battlefield). As was theorized, there is a terms of service conflict at the root of this because DICE's military shooter will include the ability to purchase DLC from within the game:

Gamers can pre-order Battlefield 3 at Origin.com as well as over 100 digital retailers worldwide. EA offers games to all major download services. Unfortunately, Steam has adopted a set of restrictive terms of service which limit how developers interact with customers to deliver patches and other downloadable content. No other download service has adopted these practices.

We are intent on providing Battlefield 3 players with the best possible experience no matter where they purchase or play their game, and are happy to partner with any download service that does not restrict our ability to connect directly with our consumers. We hope to work out an agreement where Steam can carry Battlefield 3; meanwhile, gamers can pick from the more than 100 digital retailers listed at http://www.battlefield.com/digitaldownload, or go to http://www.origin.com.

Dirwulf wrote on Aug 6, 2011, 16:23:I thought about that too. I'm replaying ME2 right now. You can't buy the DLC "in game". When you click to download it, it opens a web browser and you buy the DLC there. Then download the DLC from the web site and install it. It automatically installs it to your Steam version. This is not the same as IN GAME DLC. That's my take on it anyway. IN GAME DLC means to me, that you pay for the DLC in the game, and it downloads in the game. Kind of like when an MMO updates.

That's how Dragon Age: Origins does it, but more importantly, how Dragon Age 2 does it, as well. Why then is DA2 gone but DA:O is still on Steam? If you believe EA, it's because this Valve policy only took effect recently. However, Dragon Age 2 already had numerous DLC available for purchase in the manner you described before it was removed. It was removed on the day the Legacy DLC was released, what makes that DLC so special?

It's new. Guarantee that if another DA:O DLC were to be released in the same manner as the Legacy one from DA2, DA:O would be dumped as well.

Presumably pre-existing DLC was accounted for in some way. (The Ultimate edition for DA:O is for sale on steam including all DLC, and no future DLC is planned for it, as an example.)